Internal collapsible chuck



y 1951 J. w. WALL 2,555,170

INTERNAL COLLAPSIBLE cnucx Filed June 6, 1949 s Sheets-Sheet 1 INVENTOR.John W WQ/l 15mm, Hand!) May 29, 1951 J. w. WALL INTERNAL COLLAPSIBLECHUCK Filed June 6, 1949 3 Sheets-Sheet 2 6 Fey. /2.

INVENTOR. John W 1/l crl/ May 29, 1951 J. w. WALL INTERNAL COLLAPSIBLE0mm 3 Sheets-Sheet 3 Filed June 6, 1949 INVENTOR. John W M/cfl/ BYPatented May 29, i951 INTERNAL COLLAPSIBLE CHUCK John W. Wall, RoyalOak, Mich.

Application June 6, 1949, Serial No. 97,373

12 Claims.

This invention relates to chucks, particularly chucks for supportingsuch work as pistons that are to be turned or otherwise worked upon.

It is the object of the present invention to provide a chuck which hasthe double function I of pulling the work or piston solidly back againstthe nose of the chuck and at the same time provides expanding jaws orpins for engaging the interior of the work or the skirt of the piston.

The pull back action which pulls the work axially along the chuck iseffected by quick acting devices such as swinging dogs, while theexpanding action to grip the interior of the work is efiected by aplurality of radially movable pins.

Another feature of a modified form of the invention is an arrangementwhereby the pins are pushed out in two or more independent sets so thatif the interior of the piston skirt is out of round, the pins can gripthe interior of the skirt with substantially the same pressure,regardless at what diameter they encounter the walls of the skirt. Ifthe pins are all thrust out by one cam or member at one thrust and thepiston skirt on the interior is out of round, then the piston, whenengaged in final position on the chuck, will have the skirt distorted.It can be turned into a true cylinder on the exterior, but after thepiston is released and the deforming stress relieved, the piston willspring back to an out of round position on the exterior due to theturning while the piston is under stress and deformation. This is anobviously undesirable condition and I have obviated this by providing anarrangement and devices whereby the pins or grips are thrust out inindependent sets and independently actuated.

Referring to the drawings:

Fig. 1 is a side elevation showing my improved chuck fastened to themachine head.

Fig. 2 is a longitudinal section of my chuck.

Figs. 3 and 4 are sections on corresponding section lines of Fig. 2.

Fig. 5 is an enlarged fragmentary section of the chuck adjacent theexpanding pins.

Fig. 6 is an exploded perspective of the pull back dogs and theactuating rod.

Fig. '7 is a section on the line ll' of Fig. 2.

Fig. 8 is a section on the line 8-8 of Fig. 2.

Fig. 9 is a longitudinal section of the modified form of the inventioninvolving gripping pins actuated independently in independent sets.

Fig. 10 is a section on the line lll-ll! of Fig. 9.

Fig. 11 is a perspective of the independent actuators for the pin sets.

Fig. 12 is a longitudinal section of still another modified form of theinvention involving independently actuated pin sets.

Fig. 13 is a section on the line I3--l3 of Fig. 12.

Fig. 14 is a plan view of one of the pads which is bolted to the body ofthe chuck.

Referring to Fig. 1, I is the rotating head of the machine to which thecollar 2 of the chuck is fastened by screws 3. The chuck is providedwith a hydraulic cylinder 4 in which moves a piston 5 which ismaintained in fluid type sealing relation to the cylinder by means ofthe 0 ring 6. Some other form of actuator for moving the piston or head5 might be used. The outer piston 5 is provided at its inner end with acylinder or barrel 1 which takes the inner piston or head 8 which issealed to the cylinder wall by means of the O ring 9. The piston rod canbe fluid operated or mechanically operated. The coil spring I0 is putunder load when the outer piston moves outwardly and the coil spring His put under load when the inner piston moves outwardly with respect tothe outer piston. These two springs l0 and II return the outer pistonand the inner piston respectively to the inner position when thehydraulic pressure is relieved. The outer piston is provided with a neckor outwardly projecting rod l2 which is guided in the shell or bearingI3 and prevented from turning by the key pins I 4 which engage in thekeyway Hi. The outer end of this piston rod is provided with four flatinclined surfaces or cams l6 which are adapted to engage the chamferedends of the gripping pins I! (see Figs. 3 and 4).

A retaining ring I8 is held in a recess under the retaining sleeve H! byscrews 20. This ring engages in slots 2! (Fig. 5) of the pins to preventthese pins irom dropping out. The retaining sleeve l9 retains thesprings 22 in place, and these engage against the shoulders 23v of thegripping pins to return the pins to the inactive, non-expanding relationwhen the actuating member is released. Hence the pins will retreat intoposition so that their ends are substantially flush with the peripheryof the ring it when the hydraulic pressure is relieved.

The inner piston 8 has a piston rod 24 guided in the interior machinedopening 25 of the neck of the outer piston. The end of this piston rodis provided with an opening 26 in which seats a pin 21 which pivots thenub 28, which oscillates in the slot 29 in the end of the piston rod.The body 30 of the chuck is provided with an end portion 3| of reduceddiameter which has a slot 32 therein in which pivots a pair of dogs 33and 34. These are the pull back dogs and it Will be noted from theshowing in Fig. 6 that the upper dog has a single spur 35 which fits inbetween the pair of spurs 36 of the lower dog. These spurs are theoperating portions of the swinging dogs. These dogs have the pick-upjaws which, when they are swung out, catch in the wrist pin openings 16of the piston and thereby pick up the piston and pull it back in solidengagement with the nose or screw plug 31 of the chuck body. Theactuating spurs 35 and 36 are actuated by the swinging nub 28 at the endof the piston rod. The nub 28 continues to deliver the thrust of the rod24 after oneof the pull back dogs has pulled its side of the piston asfar back as it will go while the other side of the piston still needssome pull back to get the piston squarely back against the nose 3! ofthe chuck. This is important as the inside surfaces of the wrist pinopenings may not always be in true alignment with each other so that thedogs will pick up the wrist pins at the same instant. The screw plug 3!forms a backing for the spring 38 which bears against the stud 39 thatengages spurs 35 and 36 to turn the jaws back into the openings 32 ofthe reduced portion of the body of the chuck when the thrust on theinner piston 8 is relieved. The pin 1| (Fig. 2) is a key engaging agroove in the stud 39 to keep the stud from turning.

Referring to Figs. 7 and 8, a locator 40 is provided for properlycentering the piston on the chuck. This locator comprises a plateprovided with four jaws 4|, one at each corner of the rectangular plate.The locator slides on the reduced body portion 10 of the chuck body.Guide pins 42 project from the body of the chuck to guide the movementof the locator. Coil springs 43 press the locator plate outwardly. Thelimit of the outward movement is imposed by the collar 44 on the reducedend portion 10 of the chuck body. When the piston is placed on the chuckthe jaws of the locator plate, which are slightly tapered, fit into thetapered interior 45 of the piston and thereby center the piston on thechuck. As the pull back dogs pull back the piston against the nose ofthe chuck the locator plate is slid back to the position shown in Fig.8, where it is at all times centering the piston on the chuck.

The operation is as follows: Hydraulic or air pressure is turned intothe cylinder 4 of the chuck (or a mechanical thrust can be used upon thepiston). Inasmuch as the exposed area of the inner piston 8 is muchgreater than the exposed area of the outer piston 5, the first action isto drive the inner piston outwardly causing the piston rod 24 to thruston the two pull back dogs and pull the piston back squarely against thenose of the chuck by reason of the swinging nub 28 of the thrust rodbeing able to deliver the thrust to the other dog after one dog hasreached the limit of its movement. Thereupon the fluid pressure on theouter piston together with the thrust communicated to the outer pistonby means of the spacing spring I I between the outer and inner pistons,serves to overcome the stress of the return spring I!) and pushes thepiston rod or neck, together with its four cam surfaces It against thegripping pins l1 spreading these and causing them to grip the inside ofthe skirt of the piston. This action is very quick and effective. Afterwork has been finished on the piston and it has been turned or machinedas 4 desired, the fluid or mechanical pressure is relieved allowing thesprings to return the two pistons, the dogs, and the pins to theirpositions of retreat. The piston can be removed and replaced by anotherpiston very quickly and the work may go on.

In the form of the invention shown in Figs. 9 to 11, a valuableimprovement is provided in dividing the expanding pins into sets whichare independently operated. Here only one fluid or mechanically operatedpiston is provided. This is the piston 46 which is returned, after thepressure is relieved, by the heavy and strong coil spring 41. Thispiston is directly pinned to the piston rod 24 which operates the dogsin the way already explained. The pins are actuated by two sets oftangs. One set 48 projects from the head or piston 49 that slides in thebearing shell 50. The other set of tangs 5! projects from the head 52which is guided on the piston rod 24. The spring 53 spaces the piston 46from the head '52 and spring 54 spaces the head 52 from the head orpiston 49. The spring 55 serves to return the piston 49 to its inactiveposition when thrust on this piston is relieved. The spring 54 serves toreturn the head 52 to its inactive position and spring 41, as alreadystated, returns the main piston 46 to its inactive position. The springsare of diminishing strength as one reads from left to right. Spring 41is the strongest spring, spring 53 the next strongest, spring 54 thethird strongest, and spring 55 is the weakest spring. The strength ofthese springs has to be carefully graduated to secure the best results,but this can be determined only by observance and trial.

The action is as follows: When fluid pressure is turned into thecylinder 4 or thrust is exerted upon this piston, this drives the pistonto the right against the strong opposition of the return spring 41. Thiscauses the pull back dogs to throw out into the wrist pin openings ofthe work and pick up the wrist pins; pulling the piston solidly backagainst the nose of the chuck. In the meantime the locator 45 hasalready centered the piston on the chuck. Thereupon the thrust of thepiston 46 is communicated to the head 52 by the spring 53. This causesone set of tangs, to wit: the tangs 5|, to travel to the right thrustinout the pins that are operated by this set or tangs. At the same timethe thrust of the head 52 is communicated by the spring '54 to the head48 thrusting the tangs 48 out and causing the companion set of grippingpins to simultaneously thrust out and engage the piston skirt. If theinside of the piston is out of round, one set of pins will grip thepiston skirt before the other, and the thrust then coming from the mainpiston will be delivered mainly to the other set of tangs and grippingpins.

With the arrangement shown in Fig. 2 all the thrust is delivered at onetime to all the pins and there is no chance for a yield. The pins all goout at an equal distance. The result is that if the inside of the pistonis out of round the piston skirt itself is distorted where the one ormore pins first meet solid resistance. Consequently. when the piston isrough machined, the periphery will be accurately round while the work ison the chuck, but when the pressure is relieved the dis torted portionor portions of the piston will return to the original positions and thepiston will be somewhat out of round on the outside. This may be withinthe tolerance allowed or may be removed by the finish grinding.

The m dification shown in Figs. 12 to 14 is a" compromise between theform of chuck shown 'in Fig. 1 and the form shown in Fig. 9. Here I usetwo sets of tangs, one set 55 and the other '51. The set 5? is connectedwith the 'inner head 58 and the set 56 is connected with the outer head59-. This outer head 59 is a piston which is guided in the cylinder 4. Athird piston or sliding head 60 is provided which has a piston rod 6|which operates the pull back dogs in the same way as in the other twoforms of the invention. Spring 62 separates the piston 6!! from theouter head 58. 63 is a vent hole for the air caught between the twopistons.

The gripping pins in the form of the invention shown in Figs. 9 and 12are assembled into the body of the chuck together with the return spring65 by means of the ring 55 which is, preferably, in order to facilitateassembly, in the form of four separate pads til (see Figs. 13 and 1e)secured to the flat sides of the reduced neck portion of the body of thechuck by means of screws 68.

The operation of the third form of the invention is as follows: Whenfluid pressure is turned into the cylinder 4, this is effected first onthe piston 68 which has the greater exposed area to drive the piston rod6! out and cause the pull back dogs to come into operation. Then thefluid pressure on piston 53 and also the thrust on spring 62, drive thetangs 5'5 out and at the same time the thrust through spring 64 drivesthe head '59 outwardly carrying with it the tangs 56 to drive the otherset of gripping pins out. If one set of gripping pins meets resistancebefore the other, then the thrust can be delivered to the other set ofgripping pins by reason of this dividing the gripping pins into severalsets and delive ing the thrust to each through the fluid pressure on onepiston and the spring connection between this piston and the otherpiston. It will be understood that there may be other ways of deliveringthe thrust to pistons 60 and 58 than by fluid pressure, so I do not wantto be limited to a fluid operated motor means.

While it is old in chucks to provide the one or more sets of expandingpins to grip the inside of the skirt of the piston, so far as I amadvised,

it is new to provide a combination of pull back devices and expandinggripping pins so coordinated and timed that the piston can be pulledback to the same position on the chuck each time, then tightly grippedin this pulled back position. This is very essential because if a fullpull back is not achieved each time a piston is set in the chuck, thenthe tools working on the piston head will cut a different wall thicknessin the top of the piston on different pistons. These piston castings arerough and the pull back devices heretofore proposed simply pull therough piston back against tapered seats that fit inside of the skirt ofthe piston. It will be obvious that the pull back of the piston will notbe the same with each casing, as in some of the pistons the rough innerskirt may fit tightly on the tapered seat before the piston has beenpulled back to properly locate the top with respect to the cutting toolused on the top. With my arrangement of pulling the piston back freefrom the gripping members and solidly against the nose of the chuck andthen expanding the skirt gripping members after the full pull back, thepiston is always pulled back on the chuck exactly the same distance andconsequently there cannot be any substantial variance in the cut of thehead of the piston.

.I claim:

1. A chuck for supporting a piston or other work, having in combinationa body which can be secured to a rotating head having thrust meanstherein, sliding means guided in the body of the chuck on which saidthrust means operate, expanding gripping members guided in said body forradial movement, pull back members secured on the body for engaging aportion of the piston or other work to be held by the chuck, andconnecting means between the said sliding means and the expandingmembers and the pull back members for causing the pull back members toact on the piston undergoing working to pull the piston solidly backagainst the chuck body and. then expand the gripping members to grip thepiston in this pulled back position.

2. The combination claimed in claim 1 in which the expanding members arepins and the sliding means has extended portions adapted to engage theinner ends of the pins to expand the pins outwardly.

3. The combination claimed in claim 1 in which the expanding members areshouldered pins, springs to return the pins into the body of the chuck,and a ring for retaining the pins and springs in the body, and taperedsurfaces on the end of a rod portion of the sliding means serving toexpand the pins to grip the work when the thrust means on the head isactuated.

4. The combination claimed in claim 1 in which the pull back memberscomprise a plurality of swinging dogs with spurs that are normallyspring pressed to positions of retreat within the body of the chuck butwhich can be pushed out when the sliding thrust means is operated, and arod connected with the sliding means that has a nub that engages thespurs on the dogs to expand them into the wrist pin openings of thepiston.

5. A chuck for supporting a piston or other work, comprising a bodyarranged to provide a support for the work and having a pair of pivotedpull back dogs having overlapping spurs and pivotally supported in aslot in the body of the chuck and a slidable rod guided in the bodyhaving on its end a pivoted nub for engaging the overlapping spursprojecting from the dogs, the pivoted nub serving to deliver the thrustof the rod to the engaging jaw of one dog after the jaw of the other doghas been stopped by meeting non-overcomable resistance.

6. The combination claimed in claim 5 provided with a spring pressedstud slidably supported in the nose of the body of the chuck forengaging the spurs 0f the dogs to cause the jaws of the dogs to retreatinto the body of the chuck when the slidable rod and the pivoted nub aredrawn back.

'7. A chuck for supporting a piston or other work, having in combinationa body provided with a, collar for holding to the head of the machine,independent sets of radially expanding and retreating pins slidablysupported in the body of the chuck, and means for separately expandingeach set of pins independently of the expansion of the other set of pinsso that one set of pins may be continued to expand after the other sethave met arresting resistance.

8. The combination claimed in claim 7 in which the said actuating meanscomprises a head slidably supported in the body and a set of tangs toexpand one set of pins, a second head and a set of tangs to expand theother set of pins, one of the heads being thrust out by thrust means andthe other head being guided in the body of auamvo the chuck andreceiving its actuation from the spring thrust delivered from the firstmentioned head through means of a coil spacing spring.

9. The combination claimed in claim 7 in which the said means forindependently expanding the pins comprises a head slidably supported inthe body, and a set of tangs to expand one set of pins, and a secondhead, and a set of tangs to expand the other set of pins, one of theheads being the piston of a motor and the other head being guided in thebody of the chuck and receiving its actuation from the spring thrustdelivered from the motor piston to the other head through means of acoil spacing spring, and spring means for returning both the slidinghead and the reciprocating piston to their inactive positions after thepressure has been withdrawn from the motor piston.

10. A chuck for supporting a piston on a machine head, having incombination a, slotted body which can be removably secured to said head,dogs pivoted to said body in said slots, spring pressed means whichnormally swings said dogs to a position of retreat in said body, alongitudinally reciprocating member having a nub adapted to contact thedogs to swing them out into the wrist pin opening in said piston to pullthe piston back against the end of the chuck body, radially movable pinssupported in said body, springs for normally keeping said pins in aposition of re- 30 2,46 ,465

treat in said body, means longitudinally guided in sliding movementabout the said longitudinally reciprocating member, said means havingcam surfaces arranged to project the pins outwardly when the means isthrust outwardly' 11. The combination claimed in claim 10 in which thelongitudinally reciprocating member is timed to first contact the dogsto pull the piston back against the chuck body and then thelongitudinally sliding means project the pins out to grip the piston inpulled back position.

12. The combination claimed in claim 10 in which the longitudinallysliding means comprises a pair of separate sliding heads and projectingtangs spring separated and adapted to independently project separatesets of pins outwardly when thrust is applied to the inner head and itstangs and through the spring separating the two heads the thrust isapplied to the outer head and its projecting tangs.

JOHN W. WALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,947,957 Tillman Feb. 20, 19342,050,828 Buell Aug. 11, 1936 Casella Feb. 22, 1949

